Dr. Leahy (MH53213) investigates spatiotemporal source estimation from combined MEG and EEG. With the whole head magnetometer (MEG80) and EEG, Dr. Leahy will test model predictions in phantoms and in the human brain, simultaneously with depth electrodes. Dr. Knight (NS21135) investigates the human prefrontal cortex by localization of cognitive event related responses, their sequence of activation, and voluntary versus involuntary attention with MEG and EEG in normals and patients with stroke Dr. Knight had to travel to Japan for whole head MEG. The MEG80 would allow larger numbers here. Dr. Sutherling, Dr. Rogers, and Dr. Taylor (NS20806) investigate localization of the epileptogenic zone intractable partial epilepsy considered for surgery. The MEG80 would increase the number of patients studied and give complete maps of single spikes and seizures. Study section stated a whole head MEG system was essential to future research. Dr. Jack (NS28374) investigates memory function after epilepsy surgery compared to volumetric MRI resections. Recording and localization of cognitive responses with the MEG80 would give converging physiological evidence about the deep temporal brain regions involved in memory deficits. Dr. Rausch (NS31277) investigates long term outcome of memory on a detailed neuropsychometric battery after temporal lobectomy compared to extent of resection: on MRI, she has found different subgroups with worse versus better memory function. Localization of cognitive responses on the MEG80 will help to identify the parts of hippocampus responsible for the difference between these subgroups. Dr. Zaidel (NS20187) investigates the specialization and lateralization of hemispheric function in patients after commissurotomy. He has found differences in the functions of the two isolated hemispheres and will use the MEG80 to separate the different cortical regions involved. Dr. Chugani(NS34488) investigates Flumazenil PET to identify focal epileptogenic zone(s) when there is ambiguity in FDG PET or no structural lesion in MRI. He originally proposed MEG localization as physiological converging evidence and will use the MEG80 to enhance this research. Dr. Halgren (NS18741) uses MEG and will increase the number of subjects studied due to the centralized location of the MEG, EEG, fMRI, and intracranial electrodes in the same city. Dr. Sigman (NS25243) investigates attention in autism and will use the MEG80 to study different P300 components to resolve a controversy on attention anomalies in autism. Dr. Cohen investigates simultaneously active cortical regions in human somatotopy and covet mental activity and will use the MEG80, fMRI, and EEG to reduce the spatio-temporal inverse problem. Dr. Hegde investigates aphasia and than the relation between brain and language functions. The MEG80 has a selective advantage in resolving sources in major fissures during cognitive responses.